Fire-alarm.



'rEs PATENT oririon.

FRANK HERBECK, or A'IHOL, MASSACHUSETTS.

FIRE-ALARM.

Specification of Letters Patent.

Patented Aug. 25, 1914..

Application filed April 7, 1913. Serial No. 759,320;

To all whom it may) concern: 7

Be it known that I, FRANK HER ECK, a

V citizen of the United States, residing at Athol, county ofWorcester, Commonwealth of Massachusetts, have invented certain new and useful Improvements in Fire-Alarms,

of which the following is a specification.

This invention relates to thermal controlling devices and particularly to a thermal circuit closer for alfire alarm. Of the several types of such devices my invention pertains to that class in which contact is usually made by the melting of some substance. This class of devices has been favored on account of its simplicity and cheapness but has been open to considerable objection onaccount of the time required to melt the fusible element. In my invention I have avoided this difficulty by constructing my apparatus in such a way that a complete fusing is not necessary. In fact my invention depends more upon the change of the co-efiicient of friction due to the heat rather than to any more general fusing of the substance. In brief, I secure the results desired by employing a wedge shaped plug having a bearin surface which at normal temperatures 0 ers a high co-efiicient of friction, While at higher temperatures has a lower co-efiicient of friction. v

The construction and principle of my invention will be more fully disclosed in the specification which follows, and as illustrative of the same I have shown in the annexed drawings an embodiment which I have found well adapted for the purposes intended.

Throughout the specification and drawings like characters of reference are employed to indicate corresponding parts, and

in thesedrawings:

Figure 1. is a plan view of an alarm device in accordance with my invention. Fig. 2 is a longitudinal, central section on the line 22 of Fig. 1, illustrating in dotted lines the movement of the contact finger to circuit closing position. Fig. 3 is a longitudinal section on the line 33 of Fig. 2, and Fig. l'is a transverse section on the line 44 of Fig. 1. I v

The alarm device thus illustrated comprises a base 1 which is preferably a block of some. non-conducting material such as hard rubber or porcelain. I have indicated at 2 and 8 binding posts mounted on said base block and connected the lead wires 1- and .5 to an audible signal (not shown), such as an electric gong. These binding posts carry contact stripsG and 7 fastened to the under face of said block 1 by the contact screws Sand 9 which may be counterl sunk in the base 1.- Mounted on the upper face of the block 1 and held in place by the contact screw 8 is a spring contact finger 10 extending longitudinally of the block and inclosed in a.

housing 11 fastened to said block by the screws12. .-The,free end of said strip 10 is normally held above and out of contact with the screw 9 by a bail shaped metal strip 13 fastened tosaid contact strip 10 and projecting upwardly through the housing. This bail shaped strip is' normally held in such raised position by a wedge shaped plug 14: of some fusible material resting on the top wall of the housing and forced under the bail by. a 'relative transverse movement thereacross.

At normal temperatures the bearing surface of the plug has a relatively high 00- eflicient of friction. This frictional engage- ,ment reduces the liability of the plug being accidentally displaced to a minimum. But as the increasing temperature approaches the fusing point of the plug its bearing surface is gradually softened, thus reducing its co-efiicient of friction. This permits the plug to be dislodged by the gradual slipping down .due to its wedge shape. VVhile the plug is slipping down, the contact finger 10 is gradually being lowered and is exerting a strong tendency to eject the plug from the retaining bail due to the spring of the metal of said contact finger. The plug will therefore be immediately ejected from the holder without the necessity of having it entirely melted. This releases said holder and permits the spring contact 10 to descend and make contact with the screw 9, thereby closing the circuit in which the annunciating devices are Wired up.

I find that wax properly compounded to soften at the desired temperature makes a very satisfactory material for a plug.

In use, a house or other building to be protected is equipped with a number of these devices, each device being connected in circuit with any annunciator which will 7 sound an audible or'display a risilalsignal. preferably the formcr,-wlmn the contact fin terial gives to my device great promptness and certainty 0t action. This plug, by

reason. of its. shape,.will begin to slip as soon as it softens and will therefore be iminmliately ejected from the holder withoutnecessitating its being melted entirely. This insures the announcement ofthe fire substantially as soon as it starts,

Various modifications in the construction and torniof my device, corning within its spirit and scope may obviously be resorted to all within the'liinits the appended claims. I lj .lVhat I theretore, claim. and desire to secure by Letters Patent is:

1. In a device ol thc'class described inirmally-opcu annuncia'tor '(ftI'CllliJ a circu t closer normally disposed in non circuit closing rtdation thereto, a retaining member for said circuit closer, a bearing member, a their 'malcontrol element cjectabl'y held by said retaining IIKDd'KI against said bearing member-with a hearing which has a relatively high mellicicnt of friction under normal tcuigicraturcs cltec'tii'e'to hold said element against dii ilaceinent and which bearing has a relatively lower coefficient of friction under abnornml rises in temperature effective to permit said clement to be ejected from the retaining: member and the circuit closer to more to circuit closing, position and actuate the an nunci ator.

"2. In a device of the class described, an

anuunciator circuit, 'a normally open circuit closer. asupportirig i'ncn'ibe'r having" a beariugr surta ,-.c. a thermal ,clcment having; a l)(:1l'lll on the bearing surface of the support and spaced from said circuit closer by said support. a retainingmember for said circuit closer cicctahly holdingsaid thermal element ae ains said support with a. hearing which has a relatively high coeflicicnt-oi lrictiou under normal temperatures and a relative y lower coe'tlicicnt of friction under abnormal temperatures. said element being normally cticctive to maintain said circuit closer in open position while held by said retaining" member and being: ejected from said retaining" member by the lowering of its cocllicic'ut of friction to pcrn'iit the circuit closer to moreto circuit closing position and actuate the annunciator.

A device of the classdescribed comprisinc a contact normally held in open circuit witlran ai'munciator and eilective when re leascd to close said circuit and actuate said annunciaton a holding device connected with said contact. and a fusible plug frictionally engaged. with said holding device near its free end, and a wed" and effective tohold said contact in, non-Q circuit closing" position 'iuidernormaltclu' peraturcs by its irictiona l 'cngcragrcment with said-holdcrand adapted to release said contact to'peruiitit to close the circuit when its when released to close said circuit and :to

actuate the annunciaton "and means nor-Y mally effective to hold sa-ldf'contact in open circuit includingfla'member spacedfrom said contact, a. member connected tor-said contact, and awedgej shapedff hers under ordinary temperatures but dis placea'ble by thesoftenin dfjltsfbetlrlllg surfice under an increaseantemperature soas to be e ected from its "engagement wlth said members under the S p11l'lg, lCt10Il of the contact to permit said contactztoclose the circuit. I

5. A device of the class described com-, prising an insulated base, terminals mount- M ed thereon "in electrical circuit withen annunciator, a contact operatiyel as'soclated with said terminals, a housin f r said Q0n-' levice fastened H V I V to the base, a contact fingei heldiby one of said screws to said base an hav'ni "Its free i i 2" i end normally held above and out'of 'contact with the other of'said screu' bailfshaped retaining member fastened to sai d' contact sh-a-pedfnsible plug adapted to be insertcc tainiup; member and normally hold said member and tli'us' 't ontact ting-jet out of circuit closing osition and adapted when softened by a rise im-temperature to be ejected from said' firetaininil mom 1 her and permit-it and thus-the Contact to descend and close the circuit.

7. In a device of the class annunciator circuit, a circuit-log T mal element having a relatively igh c0- cliicient of friction undermorinh tem pera- I turcs and a relatii 'ely lower co efiicient of friction under abnormal temperatures and ell'cctirely disposed relative to said: Closer i": ictional engagement with the holder is reduced by the softening of its bearing surface under an increase in temperature.

A device ot' the class described coinpris in'g asprine contact normally heldinopeng circuit with an annunciatoifl and etfcctive p v nsible plug. normally finding bearing betweensaid'mem In testimony whereof I affix my signature in presence of two w1tnesses.

FRANK HERBECK.

\Vitncsses GEORGE F. LORD, JOSEPH A. DUNB'AR. 

